Fastener driving device



Defi 1959 H. w. MARANO 2,917,747

FASTENER DRIVING DEVICE Filed Dec. 4, 1956 2 Sheets-Sheet 1 INVENTOR #5225227 M/i l/mmvo /36 /o H4 BY W lwm we. flaw.

/6I6' ATTORNEY Dec. 22, 1959 H. w. MARANO FASTENER DRIVING DEVICE Filed Dec. 4, 1956 2 Sheets-Sheet 2 do 552 M INVENTOYR #:RPERT M mama ATTORNEY United States Patent FASTENER DRIVING DEVICE Herbert W. Marano, Summit, N.J., assignor to Wilson Jones Company, Chicago, ill, a corporation of Massachusetts Application December 4, 1956, Serial No. 626,246

7 Claims. (Cl. 1--49) The present invention relates to an improved fastener driving device, and it relates more particularly to an improved staple gun tacker.

The conventional staple gun tacker is of two general types, those in which the staple driving blade is directly manually motivated to insert and clinch the staple and those in which an energy storing spring is loaded and then released to effect the driving and, if desired, the clinching of the staple. It is with this latter type of spring loaded staple driving gun that the present invention is principally concerned and which is usually employed in the industrial type of stapling devices as distinguished from the domestic or oifice type of stapler. In the spring loaded staple driving guns heretofore available the driving blade is retracted and the spring loaded by means of a manually operated arm or lever which requires the application of a radically increasing force or pressure as the spring is brought to its fully loaded condition. As a result, the amount of force necessary to effect the operation of the conventional industrial staple driving gun is very high, particularly just prior to the delivery of the staple, as to render its uses both difficult and highly inconvenient.

It is thus a principal object of the present invention to provide an improved fastener driving device.

Another object of the present invention is to provide an improved staple driving gun.

Still another object of the present invention is to provide an improved staple driving gun of the spring loaded type.

A further object of the present invention is to provide a spring loaded staple driving gun characterized by an improved spring loading arrangement.

Still a further object of the present invention is to provide an improved staple driving gun requiring a reduced manipulating or motivating force immediately prior to the staple driving stroke.

The above and other objects of the present invention will become apparent from a reading of the following description, taken in conjunction with the accompanying drawings which illustrate a preferred embodiment of the present invention, wherein Figure 1 is an exploded view of the improved staple gun tacker;

Figure 2 is a longitudinal sectional view of the assembled staple gun tacker with the driving blade illustrated in advanced position;

Figure 3 is a view similar to Figure 2 shown partially broken away and illustrating the driving blade in fully retracted position prior to release thereof;

Figure 4 is a view similar to Figure 3 illustrating the driving blade immediately following release and advance thereof;

Figure 5 is a perspective detailed view of the staple pushing member;

Figure 6 is a sectional view of the staple pushingmember, taken along line 67-6 in Figure 7; and

Figure 7 is a sectional view of the staple pushing member, taken along line 77 in Figure 6 In a sense, the present invention contemplates the provision of an improved fastener device comprising a drive member movable between an advanced and retracted position, spring means normally urging said drive member to an advanced position, a movable motivating arm and a spring loading motion transmitting system coupling said spring means to said motivating arm and affording an increasing mechanical advantage from said'motivating arm to said spring means with the loading of said spring means.

Referring now to the drawing which illustrates a preferred embodiment of the present invention, the numeral 10 generally designates the body member of the improved staple gun tacker which includes a pair of laterally spaced parallel symmetrically formed side plates 11 having aligned finger receiving openings 12 formed therein. The plates 11 are interconnected by a plurality of component-supporting bolts, as will be hereinafter set forth, to form a rigid support and is provided with a tubular finger grip 13 which registers with the openings 12 having grooved flanges 14 engaging the corresponding edges of the openings 12, the member 13 being formed of rubber or other suitable resilient material. The upper forward edges of the plates 11 have upwardly forwardly directed lugs 16 formed thereon, the lugs being provided with horizontally aligned circular openings 17 and horizontally aligned slots 18. Directly below the lugs 16 the forward edges of the plates 11 are bent inwardly to form laterally spaced flanges 19 and the lower forward. corners of the plates 11 are provided with forwardly projecting arms 20 having aligned circular openings 21 formed therein. A front channel member 22 includes rearwardly projecting side walls 23 which engage and sandwich the lugs 16 and arms 20 and the forward edge of the plates 11, the side walls 23 having openings 24 and 26 which register with the openings 17 and 21 respectively formed in the lugs 16 and arms 20 and laterally aligned openings 27 which register with corresponding openings 28 formed in the body member side plates 11.

An operating lever or arm 28 is provided with depending aprons 29 which have laterally aligned openings 30 formed in the forward portion thereof and laterally aligned openings 32 formed in an area rearward of the forward edge of the handle 28. The forward portions of the aprons 29 engage between the opposite faces thereof the upper portion of the front channel member 22, the openings 30 registering with the openings 24 and the openings 17 formed in the side plates 11. An internally threaded hollow bolt 33 registers with the openings 17, 24 and 30 and is engaged by a suitable screw 34. A hairpin type spring 36 is carried by the bolt 33 and has a leg 37 bearing against the upper wall of the actuating lever 28 and a leg 38 hearing against a plate, as will be hereinafter described, whereby to urge the lever 28 counterclockwise to its raised position. The upward movement of the free end of the lever 28 is limited by the abutment of the forward edge 39 of the lever 28 with the confronting edge 40 of the front wall 41 of the front channel member 22.

Vertically slidably disposed in the space defined by the front channel member 22 and the forward portion of the body member 10 is a drive blade carrying ram 42 which includes a front wall 43, rearwardly projecting side walls 44 carrying the rearwardly directed brackets 46, the bottom portions of the front wall 43 and side walls 44 being rearwardly and inwardly bent respectively to form a multi-layered bottom wall47 having a vertical opening formed therein. Arivet 48 has a shank passing through the opening formed in the wall 47 and is upset to effect a rigid connection, the rivet 48 being provided with an upright cylindrical seat portion 49. Disposed on the ram front face 43 is a depending rectangular drive blade 50 formed in the conventional manner preferably of a hardened spring steel. The drive blade 50 is secured to the ram front face 43 by means of suitable rivets and has its upper edge in abutment with a pair of ears 51 formed in the ram front wall 43.

An upper spring plate 52 is provided with a pair of laterally projecting lugs 53 which engage the slots 18 formed in the body member side plates 11. A spring seat 54 has an upstanding shank registering with an opening 56 formed in the spring plate 52 and a circular head 57 abutting the underface of the plate 52, the head 57 having a depending cylindrical member 58. A pair of concentric helical energy storing compression springs 59 and 61 respectively are entrapped between the spring retaining plate 52 and the ram base 47, the opposite ends of the inner helical spring 61 registering with the cylindrical members 49 and 58 and the opposite ends of the outer cylindrical spring 69 registering with the head 57 of the member 54 and with the head of the rivet member 48. It is thus apparent that the springs 59 and 6t normally urge the ram 42 and the blade 56 to its lower or advanced position. A cylindrical cross bar 63 is provided with a pair of axially projecting stub elements 64 which engage corresponding aligned openings 65 formed in the rearwardly projecting ears 46 and peened over to effect the rigid securing thereof.

The mechanism for raising the ram carrying blade 42 and loading the springs 59 and 6t and thereafter releasing the same to effect the staple driving stroke includes two pair of laterally spaced parallel bell crank members 67 having aligned openings 68 formed in the knee portion thereof. An axle member 69 is provided with end portions 70 of reduced cross section which rotatably engage the opening 68 formed in the bell crank 67 and register with openings 71 formed in the body member side plates 11. The normally upwardly directed legs 72 of each of the pairs of hell cranks 67 engage between their opposite faces respective links 73, the lower ends of the links 73 and the upper ends of the bell crank legs 72 having aligned openings therein which are rotatably engaged by a pin 74, the pin 74 in turn carrying a spacer element 76 located between the confronting faces of the inner bell cranks 67. The upper ends of the links 73 are likewise provided with openings 7 77 which are engaged by an internally threaded hollow bolt 78 registering with the openings 32 formed in the lever apron 29, the bolt 78 being fastened by a suitable screw 79.

A pin 80 registers with laterally aligned openings formed in the forward ends of the lower arms of the bell cranks 67 and carries spacers 81 between confronting faces of the opposite pairs of hell cranks 67. A spacer 82 is also carried by the pin 80 between the confronting faces of the inner bell cranks 67 to provide spaces between the ends of the spacer 82 and the adjacent faces of the bell cranks 67. Depending from and swingably carried by the pin 80 at points adjacent the confronting faces of the inner bell cranks 67 are a pair of ram engaging hook elements 83 which are rigidly interconnected by a cross piece 84. The forward edge of each of the hook elements 83 is provided with a rearwardly directed recess 86 of greater height than the diameter of the cylindrical cross bar 63 carried by the ram 42. The forward edges of the hook elements 83 extending upwardly from the upper edges of the recesses 86 are inwardly inclined as at 87 to define a tripping cam surface and the forward edge of the hook elements 83 extending below the recess 86 are likewise inwardly inclined as at 88 to define a magazine unlatching cam surface. A hairpin spring 90 is carried by a pin 91 which is supported in the aligned openings 92 formed in the lower arms of the bell cranks 67. The spring 90 is provided with a first arm 94 which bears against the cross bar 84 and the second arm 96 which bears against the pin 74 to normally urge the hook elements 83 in a clockwise direction as viewed in the drawings. A tripping bar is defined by the interally threaded bolt 97 which passes through the aligned openings 27 and 28 formed in the front channel 22 and the body member side plates 11 and is secured by a suitable screw 98.

A bumper plate 99 is supported in and registers with a pair of laterally spaced slots 100 formed in the side walls of the front channel 22. A bumper formed of nylon or other suitable material includes a cylindrical head portion 101 which rests on the plate 99 and a depending shank 102 which registers with the corresponding hole formed in the plate 99.

A longitudinally extending bar 183 is provided with laterally extending openings 104 and 166 adjacent the forward and rear ends of the bar 183. The openings 106 of the bar 103 are engaged by an internally threaded bolt 187 which passes through openings 108 formed in the lower rear corners of the body member side plates 11, the bolt 107 carrying spacers 189 disposed on opposite sides of the bar 163 and being secured in position by a screw 110. The forward opening 184 of the bar 103 is similarly engaged by an internally threaded bolt 111 which registers with the body member side openings 21 and the front channel openings 26 and carries spacers 112 on either side of the bar 103 and is secured in position by a screw 113. It should be noted that the front edge of the bar 163 is spaced an adequate distance from the confronting face of the front channel cross arm 41 to define a guide way for the reciprocating drive blade 50.

A latching element 114 is in the shape of a rectangular frame having a front cross leg 116 slidably registering with the recess 117 formed in the bar 103 and a rear cross arm 118 slidably registering with the recess 119 formed in the upper face of the bar 103. A pair of openings 120 are formed in the rear corners of the latch member 114 and an upward rearwardly directed ear 121 is located along the rear edge of the cross piece 116. The latch member forward arm 116 is provided with laterally extending fingers 122 which slidably project through and beyond horizontal slots 126 formed in the body member side plates 11, and slidably register with recesses 127 formed in the lower rear edge of the front channel side walls 23.

Disposed directly above the bar 103 in the vicinity of the rear recess 119 is a latching member retaining plate 128 having laterally projecting lugs 129 registering with corresponding slots 130 formed in the body member side plates 11. The forward edge of the retaining plate 128 is disposed rearwardly of the rear edge of the latch member lug 121 when the latter is in its rear closed position. A pair of helical tension springs 132 have forward hook portions engaging latch member openings 120 and rear hook portions engaging corresponding tongues 133 formed on the inner face of the body member side plates 11 to normally urge the latch member to its rearward closed position.

The staple magazine includes a channel-shaped member 134 provided with upstanding side walls 136 having enlarged rear end portions defining brackets 137. A pair of aligned openings 138 are formed in the brackets 137 and are engaged by the bolt 107 to provide a hinged connection between the body member 10 and the staple magazine. A pair of upstanding ears 139 are formed in the channel side walls 136 adjacent the front end thereof and have leading edges 140 which match the trailing edge 141 formed in the lower rear edge of the channel side walls 23 and are provided with recesses 142 which are in alignment with the recesses 127 formed in the channel side walls 23 and are engaged by the latching member side ears 122 when the magazine is in closed and locked position.

A staple guide 143 of inverted channel shape having depending side walls 144 is secured to the magazine base 134 and has formed in its side walls 144 longitudinally extending recesses 146 terminating in turn with a depression 147. The staple guide 143 terminates at a point just rearwardly of the vertical path of the blade 50 and has formed in its rear lower corners openings 148. A saddle-shaped staple pusher 149 straddles the staple guide 143 and is provided with depending walls 150 having formed therein parallel horizontal slots 151. A locking member 152 registers with the slots 151, its upper surface abutting the edges of the recess 146 whereby to retain the staple pusher 149 and permit its sliding along the staple guide 143. Rotatably supported on the magazine base side walls 136 adjacent the forward ends thereof by means of suitable rivets 153 are a pair of pulleys 154. A pair of helical tension springs 156 have their rear ends engaged by lugs 157 projecting inwardly from the inner faces of the base member side walls 136, pass about the pulleys 154, and have their forward ends engaging openings 158 formed in the ears projecting laterally from the pusher locking member 152. The pusher member is thereby spring urged to its advanced position and when fully retracted seats in the depression 147 but is released upon the closing of the magazine. A more detailed description of the operation of the magazine is given in the copending application of Herbert Marano Serial No. 620,277, filed November 5, 1956.

A double hairpin spring 159 registers with the spacers 109 and is provided with a cross piece 160 registering with the slot 161 formed in the bar 103 and is also provided with depending legs 162 which engage the openings 148 formed in the staple guide 143 to normally spring urge the magazine to an open position. Mounted on the forward end of the base member 134 is a nose piece 164 having rearwardly directed ears 165 which are provided with openings aligned with corresponding openings formed in the base member side walls 136 and is suitably secured thereto by rivets 163. The upper edge of the nose piece 164 conforms in contour with the lower edge of the front channel front face 141 so that interfitting is effected when the magazine is in closed position.

In operation, the handle 28 is raised to urge the lower end of the hook elements 83 between the latching element ear 121 and the leading edge of the retaining plate 128 to shift the latching member to a forward position and out of engagement with the slots 142 formed in the base member ears 139. The base member is then swung into open position by the springs 159 to permit the loading of the magazine, the pusher element being manipulated into registry with the depression 147. After the insertion of the staples on the guide 143 the magazine is swung to closed position resulting in the releasing of the staple pusher and in the locking of the magazine by the latching member 114.

In effecting the driving of a staple, the base of the gun is brought into contact with the workpiece and the handle 28 depressed. The bell cranks are thus caused to rotate about the axle 69 through the connecting links 73 thereby raising the hook elements 83, the ram 42 and the drive balde 50 and loading the springs 59 and 60. As the ram is brought to its topmost position the tripping bar 97 bears against the hook element cam surface 87 to force the latter rearwardly to carry the recess 86 in the hook element out of engagement with the ram cross bar 63. The ram is thus released and the loaded spring drives the ram downwardly carrying the drive blade 50, the lower edge of which engages the cross arm of an aligned staple to effect the driving of the staple. As the arm 28 is released it is swung to its normal position by the spring 36 as illustrated in Figure 2 of the drawing and the hook elements 83 are carried downwardly swinging rearwardly as the lower cam surface 88 engages the cross bar 63 and being swung forwardly by the spring 90 when the hook element recess 86 registers with the cross bar 63 to the position illustrated in Figure 2 of the drawing. It is important to note that as the arm 28 is depressed to raise the ram and compress and load the energy storing springs 59 and 60 the mechanical advantage from the arm 28 to the depending hook elements 83 and hence to the springs 59 and 60 and ram 42 increases. This presents a great advantage over existing staplers since the maximum force required to operate the staple driving gun is greatly diminished, particularly at the termination of the spring loading stroke.

In a specific form of the subject staple driving gun the length of the handle from the hinge point thereof defined by the bolt 33 is 4.50 inches and the distanceof the link connecting pin 78 from the pivot bolt33 is 1.375 inches. The angle between the vertical and horizontal arms of the bell crank 72 is 98, the distance between the pin 80 and the pin 69 being 1.25 inches and between the pin 69 and the pin 74 being .66 inch, the distance between the pins connected by the links 73 is .875 inch and when the staple gun is in its normal rest condition as illustrated in Figure 2 of the drawing, the bell crank arms 72 are substantially vertical and the angle between the bell crank vertical arms 72 and the links 73 is approximately 42. At this point, the mechanical advantage between the end of the arm 28 and the ram raising hook element 83 is approximately 1.3. At about the middle of the spring loading stroke the vertical arm 72 of the bell crank forms an angle of about 26 to the vertical and the mechanical advantage form the end of the arm 28 to the hook element 83 is approximately 2.75. At the end of the stroke the arm 28 is almost horizontal and the bell crank arm 72 forms an angle of 39 to the vertical and the mechanical advantage of the arm 28 to the hook element 83 is approximately 10.75. Thus, with the above dimensions the force which must be applied to the handle 28 decreases with the raising of the ram 42 and with the loading of the springs 59 and 60 approaching the releasing of the ram. It should be noted, however, that the various dimensions may be changed to effect any desirable mechanical advantage relationship. It is an important feature of this invention that the mechanical advantage increase from the handle to the energy storing spring as the spring is loaded.

While there has been described and illustrated a preferred embodiment of the present invention, it is apparent that numerous alterations and omissions may be made without departing from the spirit thereof.

I claim:

1. An improved staple driving gun comprising a horizontally longitudinally extending body member, a staple magazine carried by said body member and including a staple carrying guide terminating in a leading end adjacent the forward bottom portion of said body member, a ram vertically slidably located adjacent the forward portion of said body member and vertically movable be tween advanced lower position and retracted upper position, a drive blade secured to and depending from said ram and movable therewith along a path disposed forward of the leading end of said staple guide, spring means urging said blade carrying ram to its advanced position, a longitudinally extending motivating arm having a forward end pivoted at a first point to the upper forward portion of said body member and a rear end rockable about said first point in a substantially vertical direction, a bell crank pivoted to said body member at a second point below and posterior to the forward end of said motivating arm and including an upwardly directed first leg and a forwardly directed second leg, a forwardly upwardly directed link connecting said first leg to said motivating arm at a third point posterior to said first point, the perpendicular to the line between said first and third points projecting from said third point traversing a path extending forward of said second point upon the depression of said motivating arm, a

catch element located on said ram, a swingable hook member depending from said second leg and having a 7 recess formed therein adapted to engage said catch element and means for effecting disengagement between said hook member and said catch element when said ram is in retracted position.

2. An improved staple driving gun in accordance with claim 1, wherein said hook member has an upwardly inwardly directed cam surface formed on the forwardly directed face thereof and said hook member disengaging means includes a bar located in the path or said cam surface as said hook member is raised.

3. An improved staple driving gun in accordance with claim 1 including spring means urging the lower portion of said hook member in a forward direction.

4. An improved staple driving gun in accordance with claim 1, wherein said link connecting said bell crank and said motivating arm is forwardly and upwardly directed when said motivating arm is in its raised position.

5. An improved staple driving gun comprising a horizontally longitudinally extending body member, a staple magazine carried by said body member and including a staple carrying guide terminating in a leading end adjacent the forward bottom portion of said body member, a ram vertically slidably located adjacent the forward portion of said body member and vertically movable between an advanced lower position and retracted upper position, a drive blade secured to and depending from said ram and movable therewith along a path disposed forward of the leading and of said staple guide, spring means urging said blade carrying ram to its advanced position, a longitudinally rearwardly extending motivating arm having a forward end pivoted at a first point to the upper forward portion of said body member and a rear end rockable about said arm forward end in a substantially vertical direction, and a spring loading motion transmitting system releasably coupling said ram to said motivating arm and including an upwardly directed lever pivoted to 'said body member at a second point below and posterior to the forward end of said motivating arm and a forwardly upwardly directed link connecting said lever to said motivating arm at a third point posterior to the forward end thereof, the perpendicular to the line between said first and third points projecting from said third point traversing a path extending forward of said second point upon the depression of said motivating arm.

6. An improved staple driving gun in accordance with claim 5, wherein said upwardly directed lever is rearwardly directed.

7. An improved staple driving gun in accordance with claim 5, wherein said upwardly directed lever is defined by a first leg of a bell crank pivoted at its knee portion to said body member at said second point, said bell crank including a second leg angularly disposed relative to said first leg and releasably connected to said arm and forming part of said spring-loading motion-transmitting system.

References Cited in the file of this patent UNITED STATES PATENTS 407,444 Newman July 23, 1889 2,285,512 Harley June 9, 1942 2,427,028 Spencer Sept. 9, 1947 2,617,097 Spencer Nov. 11, 1952 2,668,290 Heller a Feb. 9, 1954 2,719,294 Marano Oct. 4, 1955 

